Nonvolatile semiconductor memory device and manufacturing method thereof

ABSTRACT

A nonvolatile semiconductor memory device that have a new structure are provided, in which memory cells are laminated in a three dimensional state so that the chip area may be reduced. The nonvolatile semiconductor memory device of the present invention is a nonvolatile semiconductor memory device that has a plurality of the memory strings, in which a plurality of electrically programmable memory cells is connected in series. The memory strings comprise a pillar shaped semiconductor; a first insulation film formed around the pillar shaped semiconductor; a charge storage layer formed around the first insulation film; the second insulation film formed around the charge storage layer; and first or nth electrodes formed around the second insulation film (n is natural number more than 1). The first or nth electrodes of the memory strings and the other first or nth electrodes of the memory strings are respectively the first or nth conductor layers that are spread in a two dimensional state.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. patent application Ser. No. 14/724,853,filed May 29, 2015 (now U.S. Pat. No. 9,064,735 issued Jun. 23, 2015),which is a continuation of U.S. patent application Ser. No. 13/198,359,filed Aug. 4, 2011, which is a continuation of U.S. patent applicationSer. No. 13/064,559, filed Mar. 31, 2011 (now U.S. Pat. No. 8,551,838B2, issued Oct. 8, 2013), which is a divisional of U.S. patentapplication Ser. No. 11/654,551, filed Jan. 18, 2007 (now U.S. Pat. No.7,936,004, issued May 3, 2011), which are all incorporated herein byreference.

FIELD OF THE INVENTION

The present invention is related to an electrically programmablesemiconductor memory device, and particularly in such a semiconductormemory device, related to a nonvolatile semiconductor memory device.

BACKGROUND OF THE INVENTION

Demand for a nonvolatile semiconductor memory device that is small andhas a large capacity has been increasing rapidly, and a NAND type flashmemory, in which high integration and large capacitivity can beexpected, has been paid attention.

It will be necessary that a design rule should be reduced to proceededhigh integration and large capacity. For reducing the design rules,further micro processing of wiring patterns will be required.

For realizing further micro processing such as wiring patterns, a veryhigh quality of processing technique is required; therefore, reductionof the design rules has become difficult.

Thus, in late years, large number of inventions on semiconductor memorydevices, in which a three-dimensional memory cell has been suggested toraise integration degree of the memory (Japanese Patent Laid-Open No.2003-078044, U.S. Pat. No. 5,599,724, U.S. Pat. No. 5,707,885, “Masuokaet al. “Novel Ultrahigh-Density Flash Memory With a Stacked-SurroundingGate Transistor (S-SGT) Structured Cell”, IEEE TRANSACTION SON ELECTRONDEVICES, VOL. 50, NO. 4, pp 945-951, April 2003”.

Many of the conventional semiconductor memory device, in which a threedimensional memory cell is placed, need to proceed Photo Etching Process(hereinafter called “PEP”, which represents so-called a process toproceed a patterning, using photo resist and manufacturing process suchas a lithography process and etching, etc.). Here, a Photo EtchingProcess performed with a smallest line width of the design rule is setas “a critical PEP”, and a Photo Etching Process performed with a linewidth larger than the smallest line width of the design rule is set as“a rough PEP”. In the conventional semiconductor memory device, in whicha three-dimensional memory cell is disposed, it is required that thecritical PEP number per one layer of a memory cell part should be equalto or more than 3. Additionally in a conventional semiconductor memorydevice, there are many of those, in which memory cells are simplystacked, and thus cost increase caused by three-dimensionalmanufacturing will not be avoided.

In addition, in one of the conventional semiconductor memory deviceswhich placed a three-dimensional memory cell, there is a semiconductormemory device in use of a transistor of a SGT (a column shape) structure(Japanese Patent Laid-Open No. 2003-078044, U.S. Pat. No. 5,599,724,U.S. Pat. No. 5,707,885).

In a semiconductor memory device in use of a transistor of a SGT (acolumn shape) structure, a process, in which poly-silicon that willbecome gate electrodes in its side walls are formed after having formeda channel (a body) part of a stacked memory transistor part in the shapeof a pillar, is adopted. It is highly possible that problems such as ashortstop between the adjacent gates occur with micro processing,because the structure from the overhead view is the structure likeskewering dumplings.

Even more particularly, as disclosed by IEEE TRANSACTION SON ELECTRONDEVICES, VOL. 50, NO 4, pp 945-951, April 2003, after having formedupper pillar and a side wall gate, a lower layer pillar is formedregarding the upper pillar and the sidewall gate as a mask, and thus alower layer gate is formed. Therefore, as the lower the layer is going,pillar diameter is different. Accordingly, not only a variation of atransistor property occurs in every layer, but also a cell area from theoverhead view becomes large, because a pitch at the time of twodimensional placements with a pillar diameter of the bottom layer isfixed. In addition, a pair of adjacent pillars that is disposed in a twodimensional state are separated thoroughly, and an extra process thatconnects word lines of every layer will be needed. Therefore, theprocess will become cumbersome.

As for the nonvolatile semiconductor memory device of conventionalstacked type, a number of the word line driver that is necessary hasincreased because there are word lines that exist at least independentlyin every layer thus; a tip area has grown large.

BRIEF SUMMARY OF THE INVENTION

According to one embodiment of the present invention, a nonvolatilesemiconductor memory device comprising a plurality of memory strings,the memory string comprising a memory strings having a plurality ofelectrically programmable memory cells connected in series, wherein thememory string comprises a pillar shaped semiconductor, a firstinsulation film formed around the pillar shaped semiconductor, a chargestorage layer formed around the first insulation film, a secondinsulation film formed around the charge storage layer, and first to nthelectrodes formed around the second insulation film (n is a naturalnumber not less than 2); and wherein the first to the nth electrodes ofthe memory strings and the first to the nth electrodes of the othermemory strings form first to nth conductor layers spread in twodimensional, respectively.

In addition, according to one embodiment of the present invention, amanufacturing method of a nonvolatile semiconductor memory devicecomprising: forming diffusion areas having conductor impurities on asemiconductor substrate; forming a plurality of first insulation filmsand conductors in turn above the semiconductor substrates; forming aplurality of holes in the plurality of the first insulation films andthe conductors; forming a second insulation film on the surface of theholes; etching the second insulation film at the bottom of the holes;and forming a plurality of pillar shape semiconductors in the holes,respectively.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate an implementation of the presentinvention, and together with the description, explain the invention.

In the drawings, FIG. 1 is an outline diagram of the nonvolatilesemiconductor memory device according to one embodiment of the presentinvention.

FIG. 2 is a part of an outline diagram of the memory transistor area 2of the nonvolatile semiconductor memory device 1 according to oneembodiment of the present invention.

FIG. 3 is a diagram that shows an outline structure of one of the memorystrings 10 of the nonvolatile semiconductor memory device 1 according toone embodiment of the present invention.

FIG. 4 is a diagram that shows a sectional view of one memory transistorMTr in the one embodiment of the present invention.

FIG. 5 is an equivalent circuit schematic of the nonvolatilesemiconductor memory device according to one embodiment of the presentinvention.

FIG. 6 is a diagram that shows a bias state in the case that readingoperation of the data of the memory transistor MTr 3 shown by dottedlines is performed, in the nonvolatile semiconductor memory device 1according to one embodiment of the present invention.

FIG. 7 is a diagram that shows a bias state in the case that programoperation of the data of the memory transistor MTr 3 shown by dottedlines is performed, in the nonvolatile semiconductor memory device 1according to one embodiment of the present invention.

FIG. 8 is a diagram that shows a bias state of the selected block in thecase that deletion operation of the data of the memory transistor MTr ofthe selected block is performed, in the nonvolatile semiconductor memorydevice according to one embodiment of the present invention.

FIG. 9 is a diagram that shows a bias state of the no selected block inthe case deletion operation of the data of the memory transistor MTr ofthe selected block is performed, in the nonvolatile semiconductor memorydevice according to one embodiment of the present invention.

FIG. 10(A) is a diagram that shows a condition setting of a simulationof the deletion operation of one memory string of the nonvolatilesemiconductor memory device according to one embodiment of the presentinvention; FIG. 10 (B) is a diagram that shows structure of the memorystring based on the condition setting of FIG. 10(A).

FIG. 11 is a diagram that shows a plurality of adjacent memorytransistor areas in the nonvolatile semiconductor memory device 1according to one embodiment of the present invention.

FIG. 12 is a diagram that shows a calculation result based on asimulation condition shown in FIG. 10.

FIG. 13 is a diagram that shows a calculation result based on asimulation condition shown in FIG. 10.

FIG. 14 is a diagram that shows a deletion operation model of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 15 is a diagram that shows a deletion operation model of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 16 is a diagram that shows a deletion operation model of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 17 is a diagram that shows a bird's-eye view of the nonvolatilesemiconductor memory device 1 according to one embodiment of the presentinvention.

FIG. 18 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 19 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 20 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 21 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 22 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 23 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 24 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 25 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 26 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 27 is, a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 28 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 29 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 30 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 31 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 32 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 33 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 34 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 35 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 36 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 37 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 38 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 39 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 40 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 41 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 42 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 43 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 44 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 45 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according, to one embodimentof the present invention.

FIG. 46 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 47 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 48 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 49 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 50 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 51 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 52 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 53 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 54 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 55 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 56 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 57 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 58 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 59 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 60 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 61 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 62 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 63 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 64 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 65 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 66 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 67 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 68 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 69 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 70 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory-device 1 according to one embodiment ofthe present invention.

FIG. 71 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 72 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 73 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 74 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 75 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 76 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 77 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 78 is a diagram that shows a manufacturing process of thenonvolatile semiconductor memory device 1 according to one embodiment ofthe present invention.

FIG. 79 is a diagram that shows two adjacent memory transistor areas inthe nonvolatile semiconductor memory device 1 according to oneembodiment of the present invention.

FIG. 80 is a diagram that shows two adjacent memory transistor areas inthe nonvolatile semiconductor memory device 1 according to oneembodiment of the present invention.

FIG. 81 is diagram that shows a manufacturing process of the nonvolatilesemiconductor memory device 1 according to one embodiment of the presentinvention.

FIG. 82 is diagram that shows a manufacturing process of the nonvolatilesemiconductor memory device 1 according to one embodiment of the presentinvention.

FIG. 83 is diagram that shows a manufacturing process of the nonvolatilesemiconductor memory device 1 according to one embodiment of the presentinvention.

FIG. 84 is diagram that shows a manufacturing process of the nonvolatilesemiconductor memory device 1 according to one embodiment of the presentinvention.

FIG. 85 is diagram that shows a manufacturing process of the nonvolatilesemiconductor memory device 1 according to one embodiment of the presentinvention.

FIG. 86 is diagram that shows a manufacturing process of the nonvolatilesemiconductor memory device 1 according to one embodiment of the presentinvention.

FIG. 87 is an outline diagram of the nonvolatile semiconductor memorydevice according to one embodiment of the present invention.

FIG. 88 is an outline diagram of the nonvolatile semiconductor memorydevice according to one embodiment of the present invention.

FIG. 89 is a diagram that shows a plurality of adjacent memorytransistor areas in the nonvolatile semiconductor memory device 1according to one embodiment of the present invention.

FIG. 90 is a diagram that shows a plurality of adjacent memorytransistor areas in the nonvolatile semiconductor memory device 1according to one embodiment of the present invention.

FIG. 91 is a diagram that shows a plurality of adjacent memorytransistor areas in the nonvolatile semiconductor memory device 1according to one embodiment of the present invention.

FIG. 92 is a diagram that shows a plurality of adjacent memorytransistor areas in the nonvolatile semiconductor memory device 1according to one embodiment of the present invention.

FIG. 93 is a diagram showing another configuration of the nonvolatilesemiconductor memory device 1 of the present invention according to oneembodiment.

FIG. 94 is a diagram showing one example of simulation result of theimpurity distribution in the nonvolatile semiconductor memory 1 of thepresent invention according to one embodiment.

FIG. 95 is diagram showing one example of threshold change amountconsidering process difference in case of changing a gate length of theselection gate transistor in the nonvolatile semiconductor memory device1 of the present invention according to one embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description explains embodiments of the nonvolatilesemiconductor memory device and the manufacturing methods for accordingto one embodiment of the present invention; however, the presentinvention will not be will not be limited to the following embodiments.Also, in each of the embodiment, same codes are referred for the similarstructure, and will not be explained again.

An outline diagram of the nonvolatile semiconductor memory device 1 ofthe present invention according to the embodiment is shown in FIG. 1.The nonvolatile semiconductor memory device 1 of the present inventionaccording to the embodiment has a memory transistor area 2, a word linedriving circuit 3, source side selection gate line (SGS) a drivingcircuit 4, drain side selection gate lines (SGD) a driving circuit 5, asense amplifier 6, etc. As shown in FIG. 1, in the nonvolatilesemiconductor memory device 1 of the present invention according to thisembodiment, memory transistors that configure the memory transistor area2 are formed by laminating a plurality of semiconductor layers. Inaddition, the word line of each of the layers, are spread in a twodimensional state at a certain area. The word lines of each layersrespectively have a plane structure comprising the same layer and have aplate-shaped plane structure.

Further, in the nonvolatile semiconductor memory device 1 of the presentinvention according to the embodiment shown in FIG. 1, the source sideselection gate line (SGS) has a plate-shaped wiring structures, and thedrain side selection gate lines (SGD) respectively have insulated andisolated wiring structures. Also, in the nonvolatile semiconductormemory device 1 of the present invention according to the embodiment,each of the source side selection gate line (SGS) may be set to have aninsulated and isolated wiring structures, and a drain side selectiongate line (SGD) may be set to have a plate-shaped plane wiringstructures, as shown in FIG. 87. Also, in the nonvolatile semiconductormemory device 1 of the present invention according to the embodiment,each of the source side selection gate lines (SGS) may be set to have aninsulated and isolated wiring structure, and each of the drain sideselection gate lines (SGD) may be set to have an insulated and isolatedplane wiring structure, as shown in FIG. 88.

FIG. 2 is an outline structure diagram of a part of a memory transistorarea 2 of the nonvolatile semiconductor memory device 1 according to theembodiment. In the embodiment, the memory transistor area 2 has m×n ofmemory strings 10 (m and n are natural numbers) comprising memorytransistors (MTr1 mn to MTr4 mn) and selection transistors SSTrmn andSDTrmn. In FIG. 2, an example of m=3 and n=4.

Word Lines WL 1 to WL 4 are formed with conductive layers that areconnected to the gates of memory transistors (MTr1 mn to MTr4 mn) ofeach of the memory strings 10, which are applied to each of thecounterpart respectively. In other words: all of the gates of the memorytransistor MTr1 mn of each of the memory strings 10 are connected to theword line 1, all of the gates of the memory transistor MTr2 mn of eachof the memory strings 10 are connected to word line 2, all of the gatesof memory transistor MTr3 mn of each of the memory strings 10 areconnected to word line WL3, and all of the gates of the memorytransistor MTr4 mn of each of the memory strings 10 are connected toword line 4. In a nonvolatile semiconductor memory device 1 of thepresent invention according to this embodiment, as shown in FIGS. 1 and2, the word lines (WL1 to WL4) are respectively spread in twodimensional and have a plate-shaped plane structure. Also, the wordlines (WL1 to WL4) respectively have a plane structure, which is almostvertical for the memory strings 10. In addition, source side selectiongate lines SGS, which drive the source side selection transistorsSSTrmn, can be set to set as a common potential per each layer all thetime as a matter of operation. Therefore, in this embodiment, a plateshaped structure is applied for the source side selection gates SGS.

Each of memory strings 10 has a pillar shaped semiconductor on n+ areathat is formed in a P-well area of the semiconductor substrate. Each ofthe memory strings 10 is arranged within a plane being vertical to thepillar shaped semiconductor with a matrix. In addition, the pillarshaped semiconductor may be either a cylindrical shape or a prism shape.Also, a pillar shaped semiconductor includes a pillar shapedsemiconductor having stepwise shape.

Each word line WL may be set to have a spread that is equal to or morethan two times of a distance, wherein a diameter of a pillar shapedsemiconductor is added in an interval of the pillar shaped semiconductornext to each other. In other words, it is preferable that each word lineWL should have a spread that is equal to or more than two times of thedistance between centers of the pillar shaped semiconductor

An outline diagram of one memory string 10 (here shown by mnth memorystring) of the nonvolatile semiconductor memory device 1 of the presentinvention according to this embodiment is shown in FIG. 3 (A), and itsequivalent circuit schematic in FIG. 3 (B). In this embodiment, thememory strings 10 have 4 memory transistors MTr1 mn to MTr4 nm, and twoselection transistors SSTrmn and SDTrmn. The 4 memory transistors MTr1mn to MTr4 mn and two selection transistors SSTrmn and SDTrmn areconnected respectively in series, as shown in FIG. 3. In one memorystrings 10 of the nonvolatile semiconductor memory device 1 of thisembodiment, a pillar semiconductor 11 is formed in N+ area 15 that isformed in P-type area (P-Well area) on a semiconductor substrate. Also,insulation films 12 formed around a pillar shaped semiconductor 11 and aplurality of plate shaped electrodes 13 a to 13 e that are formed aroundthe insulation films 12 are formed. The electrodes 13 b to 13 e, theinsulation films 12, and the pillar shaped semiconductor 11 form memorytransistor MTr1 mn to MTr4 mn. In addition, the insulation films 12 isthe insulation film that function as charge storage layers (for example,a silicon oxide film, a silicon nitride film, a lamination film of thesilicon oxide films). For example, if the insulation films 12 include afilm that is made of a silicon oxide film, a silicon nitride film, alamination film of the silicon oxide films, what is called ONO film, acharge is held in a SiN trap disintegrated and distributed into thesilicon nitride film. The electrodes 13 b to 13 e respectively becomeword line WL1 to WL4, an electrode 13 f becomes a selection gate lineSGDn, and 13 a becomes a selection gate line SGS. Also, a bit line BLmis connected to an edge of source/drain of the selected transistorSDTrmn, a source line SLm (in this embodiment, N+ area 15) is connectedto an edge of the source/drain the selected transistor SDTrmn. Inaddition, the charge storage layer may be set to be formed around thecolumn shaped semiconductor layer 11 of the MTr1 mn to MTr4 mn (that is,the layer may be set to be localized between the pillar shapedsemiconductor 11 and the electrodes 13 b to 13 e).

In addition, a floating gate, which is formed in the charge storagelayer by a conductor, may be applied. At the time, the conductor isformed only between the pillar shaped semiconductor and each word line.

Further, an insulation film 14 functioning as a gate insulation film isformed between the electrodes 13 a and 13 f, and the pillar shapedsemiconductor 11.

Further in this embodiment, the memory strings 10 has 4 memorytransistors MTr1 mn to MTr4 mn, the number of memory transistors in amemory string is not limited to this, but may be changed accordingly toan arbitrary number depending on memory capacity.

The memory string in this embodiment of the present invention has anoutline symmetry shape to a center axis of the pillar shapedsemiconductor.

FIG. 4 is a figure that shows a cross-sectional structure of one memorytransistor MTr (for example, MTr4 mn) in this embodiment. In addition,the other memory transistors MTr1 mn to MTr3 mn have same structure withthe memory transistor MTr4 mn. In the memory transistor MTr4 mn, theconductor layer 13 e surrounding the pillar shaped semiconductor 11,functions as a control gate electrode via the insulation films 12. Thesource 20 and drain 21 of the memory transistor are formed in the pillarshaped semiconductor 11. However, for case that the memory transistorMTr1 mn, and the selection gate transistors SSTrmn and SDTrmn have adepression type transistor structure, a definite source/drain diffusionlayer may be set not to exist in a part of the semiconductor 11. Also,the pillar shaped semiconductor 11 may be set what is called anenhancement type transistor, in which an area roughly surrounded withthe conductor layer 13 e roughly is set to be a P-type semiconductor,and in which an area not roughly surrounded with the conductor layer 13e is set to be a N-type semiconductor.

In FIG. 3 and FIG. 4, explanation for one memory string 10 has beenperformed, in the nonvolatile semiconductor memory device 1 according tothis embodiment; all of the memory strings have the same structure.

Operation

First, “reading operation”, “programming operation” and “erasingoperation” in the memory transistors MTr1 mn to MTr4 mn of one memorystrings 10 according to this embodiment will be explained referring toFIG. 3. As for the “reading operation” and “program operation”explanation is held by illustrating memory transistor MTr3 mn.

Further, the memory transistors MTr1 mn to MTr4 mn in this embodimentare what is called a MONOS type transistor including semiconductor 11,insulation films (a silicon oxide film, a silicon nitride film, and alamination film of the silicon oxide film) functioning as a chargestorage layer, and a conductor layer (a poly-silicon layer in thisembodiment), here explanation will be performed with the assumption thatthreshold Vth of a memory transistor MTr with a situation that electronsare not accumulated in the charge storage layer (hereinafter called“neutral threshold”) be near 0V.

Reading Operation

At the time of data reading from the memory transistor MTr3 mn, Vbl (forexample 0.7V), 0V, Vdd (for example 3.0V), and VPW (for example, 0V) arerespectively applied to the bit line BLm, source line SL, the selectiongate line SGD and SGS, and P-Well area. Then, the word line WL3, whereinthe bit desired to be read out bit (MTr3 mn) is connected, is set as 0V,and the other word lines WL are set as Vread (for example, 4V). Herebyis determined whether current is charged to the bit line BLm, dependingupon whether the threshold Vth of the bit desired to be read out bit(MTr3 mn) more or less than 0V, and thus it becomes possible to read outdata information of the bit (MTr3 mn) by sensing current of the bit lineBLm. In addition, the data of other bits (the memory transistor MTr1 mn,MTr2 mn, and MTr4 mn) can be read out with a similar operation.

Programming Operation

At the time of programming data “0” into the memory transistor MTr3 mn,i.e., enhancing threshold of the memory transistor by implantingelectrons in the charge storage layer of the memory transistor MTr3 mn(shifting the threshold toward a positive direction), 0V, Vdd, Vdd (forexample, 3.0 V), Voff (for example 0V) and VPW (for example, 0V) arerespectively applied to bit line BLm, the source line SL, the selectiongate line SGDn, the selection gate line SGS, and the P-Well area. Andthe word line WL3 of bits desired to be programmed (MTr3) and the otherword lines WL, are further set to be Vprog (for example, 18V) and Vpass(for example, 10V), respectively. By doing so, electric field strength,wherein only the desired bits (MTr3 mn) are applied to the chargestorage layer, are strengthened, electrons are implanted into the chargestorage layer, and then the threshold of the memory transistor MTr3 mnis shifted toward a positive direction.

At the time of programming data “1” into the memory transistor MTr3 mn,i.e., the threshold is not enhanced from the erasing state of the memorytransistor MTr3 mn (electrons are not implanted into the charge storagelayer), the gate potential and the source potential of the selectiontransistor SDTrmn become equivalent potentials by applying to the bitline BLm. Therefore, the selection transistor SDTrmn becomes anoff-state, and a potential difference between the channel forming area(a body part) and the word line 3 of the memory transistor MTr3 mn aredecreased. As a result, the electron implantation into the chargestorage layer of the memory transistor MTr3 mn is not occurred. Inaddition, data may be programmed into the other bits (memory transistorsMTr1 mn, MTr2 mn, and MTr4 mn) by the same operation.

Erasing Operation

At the time of data erasing, data erasing of the memory transistors MTr1mn to MTr4 mn is performed a block unit including a plurality of memorystrings 10.

In the selection blocks (the blocks desired to be erased) Verase (forexample 20V) is applied to the P-Well area, the potentials of theselection gate lines SGS and the SGDn are enhanced (for example, to15V), setting the source line SL to be floating and sliding the timeslightly with the timing applying Verase to the P-Well area (sliding ata degree of 4 μsec, for example). By doing so, GIDL (Gate Induced DrainLeak) is occurred near the gate terminal of the selection transistorSSTrmn, and the generated holes are drained into the inside of thesemiconductor layer. 11, which is the body part of the memorytransistors MTr1 mn to MTr4 mn. On the other hand, electrons are flowedinto the P-Well direction. Thereby potential near Verase is transmittedto the channel forming area (the body part) of the memory transistorMTr, because of this, if the potentials of the word line WL1 to WL4 areset to be 0V, the electrons of the charge storage layer are pulled outinto the P-Well and thus data deletion of the memory transistors MTr1 mnto MTr4 mn may be performed.

On the other hand, when data erasing of the memory transistor isperformed, in the non-selected blocks, potentials of the channel formingarea (the body part) of the memory transistors MTr1 mn to MTr4 mn areenhanced by setting the word lines WL1 to WL4 being floating, at thesame time, potentials of the word lines WL1 to WL4 are enhanced bycoupling and there becomes no potential difference between the wordlines WL1 to WL4 and the charge storage layers of the memory transistorsMTr1 mn to MTr4 mn. Therefore, pulling out (deletion) of the electronsfrom the charge storage layer is not performed.

Next, “reading operation”, “program operation” and “erasing operation”of the nonvolatile semiconductor memory device 1 of this embodiment,wherein the memory strings 10 are disposed vertically and horizontallywith a two dimensional shape for the substrate face, are explained. InFIG. 5, an equivalent circuit of the nonvolatile semiconductor memorydevice 1 of the present invention according to this embodiment is shown.In the nonvolatile semiconductor memory device 1 of this embodiment, thepotentials of word lines WL1 to WL4 respectively have the same ones, asdescribed above. Also here, each of the selection gate lines SGS1 toSGS3 are set to be able to be controlled independently, and thesepotentials may be set to be controlled by setting them to be theequivalent potentials such as forming the selection gate lines SGS1 toSGS3 with the same conductor layer and soon.

Further in this case, “reading operation” and “programming operation” inthe memory transistor Mtr321 shown with a dotted line (a Mtr3 of thememory strings that is connected to the bit line BL2 and the selectiongate lines SGS1 and SGD1) will be explained, and “erasing operation” ofthe memory transistor will be explained.

Reading Operation

FIG. 6 is a diagram showing bias state in the case that readingoperation of data of the memory transistor Mtr321 shown by dotted linein the nonvolatile semiconductor memory device 1 according to thisembodiment is performed. Here again, explanation will be performedassuming: the memory transistor Mtr in this embodiment is what is calleda MONOS type transistor including the semiconductor 11, the insulationfilm, which function as a charge storage layer (a silicon oxide film, asilicon nitride film, and a lamination film of the silicon nitride film)and the conductor layer (a poly-silicon layer in this embodiment), and athreshold Vth (a neutral threshold) of the memory transistor Mtr in thestate, wherein the electrons are laminating in the charge storage layer,is near 0V.

At the time of data reading out from the memory transistor MTr321, Vbl(for example, 0.7V), 0V, 0V, Vdd (for example, 3.0V), and Voff (forexample, 0V), and VPW (for example, 0V; however, VPW may be anypotentials so far as the P-Well and the memory strings are not in aforward bias) are respectively applied to: the bit line BL2, which thememory transistor Mtr321 is connected to, the other bit lines BL, thesource line SL, the selection gate lines SGD1 and SGS1, in which thememory transistor MTr321 is connected, the other selection gate linesSGD and SGS, and the P-Well area. And the word line WL3, which the bit(MTr321) desired to be read out is connected to, is set to be 0V, andthe other word lines WL are set to be Vread (for example, 4.5V). Herebya potential difference occurs between the bit line BL2 and the sourceline SL of the bit (MTr321) reading out data, and the selection gateline SGD1 is in an “on” state. Because of this, whether the current isflow or not to the bit line BL2 is determined by whether the thresholdVth of the bit desired to be read out (MTr321) is large or small.Therefore, the data information of the bit (MTr321) can be read out bysensing the current of the bit line BL2. In addition, the data of theother bits (the memory transistor MTr1 mn) may be read out with asimilar operation. As this occurs, for example, the SGD2 of the memorytransistor MTr322 is Voff, despite the threshold Vth is at any valuei.e., either “1” or “0” is programmed into the memory transistor MTr322,therefore, current will not flow into the memory transistor MTr322 andthe memory strings 10 that the MTr322 belongs to. These are memorystrings 10 connected to the bit line BL2, which is similar in all of thememory strings 10 that is not connected to the selection gate line SGD1.

Also, for example, explaining with an example of the memory transistorMTr331, in the case of the memory strings 10 that MTr331 belongs to,despite a threshold Vth of the memory transistor MTr331 is at any value,i.e., either “1” or “0” is programmed into the memory transistor 322,current will not be running into the bit line BL3, because the bit lineBL3 is 0V and has same potential to the source line SL. This is commonin all of the memory strings 10 not connected to the bit line BL2.

From the above description, in the nonvolatile semiconductor memorydevice 1 of the present invention according to this embodiment, even ifthe word lines WL1 to WL4 are respectively made driven with the commonpotentials, and the selection gate lines SGS1 to SGD3 are respectivelydriven with the common potential, the data at the threshold of theoptional bits can be read.

Programming Operation

FIG. 7 is a diagram showing a bias state in the case of programmingoperation of the data of the memory transistor MTr321 shown with thedotted line, in the nonvolatile semiconductor memory device 1 of thepresent invention according to this embodiment.

In the case that data “0” is programmed into the memory transistor MTr3,i.e., the threshold of the memory transistor is enhanced by implantingelectrons into the charge storage layer of the memory transistor MTr321(shifting the threshold toward a positive direction), 0V, Vdd, Vdd, Vdd,Voff, Voff, VPW (for example, 0V), are respectively applied to: the bitline BL2, which the memory transistor MTr321 is connected to the otherbit lines, the source line SL, the selection gate line SGD1, which thememory transistor MTr321 is connected to the other selection gate lineSGD, the selection gate lines SGS1 to SGS3, and the P-Well area.Further, by setting the word line WL3 of the bit (MTr321) desired to beprogrammed to be Vprog (for example, 18V) and the other word lines WL tobe Vpass (for example, 10V), a channel is formed into all the memorytransistors except for the selection gate transistor SSTr21, which asource side selection gate line SGS1 is connected to MTr121, MTr221,MTr321, and MTr421, in the memory strings 10 that the MTr321 belongs to,then the potential of the bit line BL2 (0V) is transmitted to thechannel. Therefore, the filed strength, which is applied to a ONO filmincluding the charge laminating layer that exists between the word lineof the desired bit (MTr321) and the column shaped semiconductor becomesstrong, the electrons are implanted into the charge storage layer, andthen the threshold of the memory transistor MTr321 shifts toward apositive direction.

At this time, for example, in the memory transistor MTr322, Voff isapplied to the source side selection gate line SGD2 so that thepotential of the bit line BL2 is not transmitted to the channel part ofthe memory transistor MTr322 and thus no implantation of the electronsoccurs in the memory transistor MTr322. This is applied to the memorystrings 10 connected to the BL2, which is same to all the memory strings10, in which the memory transistor MTr321 is not belonged to.

Also for example, in the memory transistor MTr331, the source sidepotential of the selection transistor SDTr31, which the selection gateline SGD1 is connected to, becomes Vdd and the potential of the bit lineBL3 is also Vdd in the memory strings 10 that MTr331 belongs to.Therefore, the potentials of the source of the selection transistor andthe gate of the selection transistor SDTr31 become same potentials. As aconsequence, the selection transistor SDtr31 is not on, and the outerelectric potential is not transmitted in the channel part of the memorytransistor MTr331, and thus, electron implant will not occur. This issimilar to all the memory strings 10 that are not connected to the bitline 2.

In case that data “1” is programmed in memory transistor MTr321, i.e.,the threshold is not enhanced from the erasing state of the memorytransistor MTr321 (electrons are not implanted into the charge storagelayer), the gate potential and the source potential of the selectiontransistor SDTr21 become the same potentials by applying Vdd to the bitline BL2. Therefore, the selection transistor SDTr21 becomes off stateand the potential difference between the channel formation area (thebody part) and the word line WL3 of the memory transistor MTr3 becomesreduced, so that the electron implant does not occur in the chargestorage layer of the memory transistor MTr321. In addition, data of theother bits (memory transistor MTr1 mn: in an example shown in FIG. 7, lis 1 to 4, m is 1 to 3, and n is 1 to 3) may be programmed.

Also, by setting the potential of each bit line BL adequately with 0V orVdd, it becomes possible to perform a programming, namely pageprogramming simultaneously on the bit (MTr) of the common word lines WLselected by one selection gate line SGD.

Erasing Operation

At the time of data erasing, data erasing of the memory transistor MTris performed per block unit including a plurality of memory strings.FIG. 8 is a diagram showing a bias state in the case the erasingoperation of data of the memory transistor MTr of the selected block, inthe nonvolatile semiconductor memory device 1 of the present inventionaccording to this embodiment.

In the selected block (the block desired to be erased), Verase (forexample, 20V) is applied in the P-Well area, the source line SL is setto be at floating, and sliding the time slightly with the timingapplying Verase in the P-Well area (for example, sliding in the degreeof 4 μsec), and thus the potentials of the selection gate lines SGS andSGD is enhanced (for example, to 15V). By doing so, GIDL (Gate InducedDrain Leak) is occurred near the gate terminal of the selectiontransistor SSTr, and the generated holes are drained into the inside ofthe semiconductor layer 11, which is the body part of the memorytransistor MTr. On the other hand, electrons are drained into the P-Welldirection. Thereby potential near Verase is transmitted to the channelforming area (the body part) of the memory transistor MTr, because ofthis, if the voltage of the word lines WL1 to WL4 are set to be 0V, theelectrons of the charge storage layer of the memory transistor MTr arepulled out into the P-Well and thus data erasing may be performed.

On the other hand, when performing data erasing of the memorytransistors of the selected block, in the no selected block, potentialsof the channel forming area (the body part) of the memory transistorsMTr1 mn to MTr4 mn are enhanced by setting the word lines WL1 to WL4being floating, at the same time, potential of the word lines WL1 to WL4are enhanced by coupling and there becomes no potential differencebetween the word lines WL1 to WL4 and the charge storage layers of thememory transistors MTr1 to MTr4. Therefore, pulling out (erasing) of theelectrons from the charge storage layer is not performed.

Here summarization of a relationship of the potentials among “thereading out operation”, “the programming operation” and “the erasingoperation” of the nonvolatile semiconductor memory device 1 of thepresent invention according to this embodiment is shown in Table 1.

TABLE 1 Erase Erase Read Write“0” Write“1” (selection) (nonselection) BLVbl 0 Vdd Verase Verase SGD Vdd Vdd Vdd Vera_del Vera_del WL4 VreadVpass Vpass 0 open WL3 0 Vprog Vprog 0 open WL2 Vread Vpass Vpass 0 openWL1 Vread Vpass Vpass 0 open SGS Vdd Voff Voff Vera_del Vera_del SL 0Vdd Vdd open open PW 0 0 0 Verase Verase

Erasing Operation Simulation

A setting condition and a result of the erasing operation simulation ofthe nonvolatile semiconductor memory device 1 of the present inventionaccording to this embodiment are shown in FIG. 10 to FIG. 13.

FIG. 10 (A) is a diagram showing a setting condition of the simulationof the erasing operation of one memory string of the nonvolatilesemiconductor memory device of the present invention according to thisembodiment. Also, FIG. 10 (B) shows a structure of the memory stringsbased on a condition setting of FIG. 10 (A). In FIGS. 10 (A) and (B),impurity concentration of the P-Well is 1E19 cm-3, impurityconcentration of the source line SL is 5E19 cm-3 a diameter and impurityconcentration of the pillar shaped semiconductor layer (the body) wasrespectively set to be 19 nm, 1E15 cm-3, impurity concentration of thebit line BL was set to be 1E19 cm-3 (the lower layer part), 5E19 cm-3(the upper layer part), a thickness of the word line WL was set to be 50nm, a distance between each of the word lines WL was set to be 25 nm, athickness of poly-silicon of the selection gate line SGS was set to be100 nm, a diameter of a hole, in which the pillar shaped semiconductorlayer is implanted (hereinafter it may be called “a memory plug hole”),was set to be 35 nm, and the thickness of the charge storage layer FGwas set to be 16 nm (however in the simulation, the potential of FG isnot floating but a word line potential VCG). In addition, the voltageVerase that was applied to P-Well at the time of data erasing, is madeenhanced up to 20V, the voltage Vdd that was applied to the bit line BL,is made enhanced up to 20V, a voltage VSG that is applied to theselection gate line SGD was made enhanced up to 15V, and thus a voltageVCG that was applied to the word lines were set to be 0V.

FIG. 12 and FIG. 13 show a calculation result based upon the simulationcondition that is shown in FIG. 10, is shown. FIG. 12 shows a potentialchange and FIG. 13 shows a hole concentration. If the potential of theP-Well is enhanced, the potential of the pillar shaped semiconductorlayer (the body) begins to enhance having a little delay. Accompanyingwith it, the hole concentration of the pillar shaped semiconductor layer(the body) is enhancing. This indicates that electric field is onbetween the pillar shaped semiconductor layer (the body) and word linesthe erasing becomes possible by occurrence of the GIDL current at SGSgate terminal part, implant of the hole in the pillar shapedsemiconductor layer (the body), and transmission of the potentials.

Here in the nonvolatile semiconductor memory device of the presentinvention according to this embodiment, examples of the structure torealize the deletion operation is shown in FIG. 14 to FIG. 16.

FIG. 14 is an example, in which concentration of the pillar shapedsemiconductor layer (the body) of the selection gate transistor SSTrconnected to the source side selection gate line SGS is enhanced. Bydoing this, GIDL may be increased so that the holes that are necessaryand sufficient for the erasing operation may be supplied. FIG. 14 is astructure, in which the deletion method using GIDL current shown in theabove-described simulation, is realizable. In addition, this embodimentof the present invention is also realizable with the deletion method, inwhich the GIDL is not used. Such example is shown in FIG. 15 and FIG.16.

In FIG. 15, an example, in which the pillar shaped semiconductor layer(the body) and the P-Well area of the semiconductor substrate areconnected directly. In this case, holes can be implanted directly fromthe P-Well. Also, because contact with the source line SL and the pillarshaped semiconductor layer (the body) is also necessary, it is necessarythat the pillar shaped semiconductor layer (the body) and n+ diffusionarea be an overlap structure.

In FIG. 16, a method, in which holes are directly injected into thepillar shaped semiconductor layer from the P-dope poly-silicon layer ofthe substrate, is shown. It shows a constitution, in which a contactlayer including a p-type poly-silicon is formed on a n+ diffusion area,and the pillar shaped semiconductor layer (the body) contacts with thecontact layer including the n+ diffusion area and the p-typepoly-silicon.

Any structures in FIG. 14 to FIG. 16, the erasing operation of thenonvolatile semiconductor memory device of the present inventionaccording to this embodiment may be realized. In addition, thestructures explained in this embodiment are merely examples of thenonvolatile semiconductor memory device of the present invention so thatit is not limited to these structures.

Manufacturing Method

A bird's-eye view of the nonvolatile semiconductor memory device 1 ofthe present invention according to this embodiment is shown in FIG. 17.The nonvolatile semiconductor memory device 1 of the present inventionaccording to this embodiment has a structure, in which memorytransistors are laminated on the semiconductor substrate. The area, inwhich the memory transistors are laminated (memory transistor areas),can be manufactured by 5 Photo Etching Processes (3 critical PEP and 2rough PEP) without a relationship of the lamination number of the memorytransistors.

As shown in FIG. 17, each of the word lines WL1 to WL4 respectively hasa plate-shaped and a stepwise-shaped structure. Because each of the wordlines WL1 to WL4 respectively has a plate-shaped and stepwise-shapedstructure, a step occurs in the side edge parts of each of the wordlines WL1 to WL4. By using the steps, contact holes to connect a wordline driver and each of the word lines WL1 to WL4 may be manufactured bythe same photo etching process. Also, the bit lines are connected to thesense amplifier, and the selection gate line SGD is connected to theselection gate line SGD driver, using the contact holes that are formedat the same time by the photo etching process.

The nonvolatile semiconductor memory device according to one embodimentof the present invention may form a plurality of vertical typetransistors connected in series with 1 PEP, by laminating the laminationfilm corresponding to number of the lamination of the memory transistorsin advance and forming a hole pattern simultaneously.

Also in the nonvolatile semiconductor memory device 1 of the presentinvention according to this embodiment, it is necessary to connect theselection gates to the upper and lower parts of vertical typetransistors that are connected in series to operate a plurality of thevertical type transistors. Formation of the series structure with theplurality of the vertical type transistors that are connected in seriesto the selection gates, can be performed simultaneously with PEP of 1 or2 a (memory transistor formation holes PEP)

Further, the source side selection gate lines SGS of the verticaltransistor that are connected in series and each of the word lines ofeach of the memory transistors can be set as a common potential per eachlayer all the time as a matter of operation. Therefore, a plane shapedstructure may be applied to either the selection gate lines SGS and theword lines WL. As thus described, the word line may be formed by therough PEP, by which the manufacturing process may be simplified and thusthe cost reduction may be realized.

A manufacturing process of the nonvolatile semiconductor memory device 1of the present invention according to this embodiment using FIG. 18 toFIG. 44 will be explained. In FIG. 18 to FIG. 44, a peripheral circuitarea, in which a peripheral circuit areas such as a word line drivercircuit and a sensing amplifier circuit are formed are shown on the leftside, and the memory transistor area is shown on the right side. Also inthe memory transistor area, parts corresponding to an area A part, anarea B part, a cross section of X-X′ and Y-Y′ of the nonvolatilesemiconductor memory device 1 of the present invention according to thisembodiment shown in FIG. 17 are shown.

First, FIG. 18 is referred. A thin silicon oxide film (SiO2) is formedon a semiconductor substrate 1 (not shown in the figures), thensubsequently, a silicon nitride film (Si3N4) is laminated (not shown inthe figures), and in the area 102 a, 102 b, 102 c, 103 d and 102 e,which forms STI (Sharrow Trench Isolation), a shallow trench of about300 nm is formed by Dry Etching method. Afterwards, by laminating asilicon oxide film with a heat CVD method or a plasma CVD (ChemicalVapor Deposition) method, embedding the slot thoroughly with the siliconoxide film, and removing the silicon oxide film other than the part ofthe slot by Chemical Mechanical Polishing (CMP), STI (Shallow TrenchIsolation) 102 a, 102 b, 102 c, 102 d, 102 e are formed (FIG. 18). Then,the remaining silicon oxide films are removed with heat phosphorous.

Next, sacrificial oxidation is performed in the substrate surface (notshown in the figures), photoresist pattern that opens desired areas isformed, boron (B) ions are implanted, forming the P-Well area 104,afterwards, the resist is removed (FIG. 19). Next, the photo resistpattern that opens the desired areas is formed; boron (B) ions areimplanted near the surface of the substrate 100, and thus a channelimplant area 106 a and 106 b, by which a threshold of the transistor Vthis adjusted are formed. In addition, here, the transistor formed in theperipheral circuit area shows an example of N-channel type transistor;however, N-Well area is formed and thus P-channel type transistor isformed (not shown in the figures) by implanting ions giving the N typein the desired area.

Next, the photo resist pattern, in which only the memory transistorareas is open, is formed, a phosphorous (P) ions are implanted only inthe memory cell transistor area, and thus n+ diffusion area 107 isformed (FIG. 20) The n+ diffusion area 107 becomes the source line SL.

Next, the sacrificial oxidation film (not shown in the figures) isremoved, and thus a first gate insulating film (not shown in thefigures) is formed.

Next, photo resist masks 108 a and 108 b are formed in the desiredpattern, and Wet Etching is performed, by doing so, the first gateinsulation film at the desired position and a part of STI102 a and 102 bare etched and removed (FIG. 21). A thin film gate transistor for highspeed operation is formed in the area, and the thick gate transistor forhigh resist pressure will be formed in the area, where no Wet Etching isperformed.

Next, the photo resist mask 108 a and 108 b are removed so that a secondgate insulation film (not shown in the figures) is formed. And apoly-silicon (p-Si) film 110 adding conductive type impurities such as P(phosphorus) are formed on the substrate (FIG. 22). And the poly-siliconfilm 110 is etched with a predetermined pattern, then gate electrodes110 a and 110 b of the transistor of the peripheral circuit area areformed (FIG. 23). Next, photo resist is formed in the P-channel typetransistor area of the peripheral circuit area and the memory transistorarea (not shown in the figures), P (phosphorus) ions or As (arsenic)ions etc., are implanted into the N-channel type transistor area in theperipheral circuit area, the N-channel type areas 112 a, 112 b, 112 cand 112 d that are automatically shallow are formed with the gateelectrode 110 a and 110 b (FIG. 23). Then the photo resist is removed.

Next, photo resist is formed in the area of N-channel type transistorand the memory transistor area of the peripheral circuit areas (notshown in the figures), B (boron) ion etc., are implanted in theP-channel type transistor area of the peripheral circuit areas, a P-typearea (not shown in the figures) that automatically shallow are formedwith the gate electrode (not shown in the figures), and then, the photoresist is removed.

Next, silicon nitride film is formed on the whole surface of thesubstrate and by performing anisotropic etching, the silicon nitridefilms are remained only in the both edge part of the gate electrode 110a and 110 b, thus side walls 114 a, 114 b, 114 c and 114 d are formed(FIG. 24).

Next, photo resist is formed in the P-channel type transistor area inthe peripheral circuit area and the memory transistor area (not shown inthe figures), arsenic (As) ions are implanted in the N-channel typetransistor of the peripheral circuit areas, a source/drain areas 116 a,116 b, 116 c and 116 d are formed automatically shallow with the sidewalls 114 a, 114 b, 114 c and 114 d (FIG. 25), and then, the photoresist is removed.

Next, photo resist is formed in the N-channel type transistor area ofthe peripheral circuit area and the memory transistor area (not shown inthe figures), boron (B) ions are implanted into the P-channel typetransistor area of the peripheral circuit area, the source/drain areasare formed automatically shallow with the side walls (not shown in thefigures), and then, photo resist is removed.

Next, a silicon nitride film (a barrier silicon nitride film) 118 isformed on the whole surface of the substrate (FIG. 25).

Subsequently, BPSG (Boron Phosphor Silicate Glass) film 120 is formed inthe whole substrate, and by performing CMP treatment, a BPSG film 120 isplanarized (FIG. 26). And by forming cobalt (Co) film on the wholesurface of the substrate by a spattering method and performing a heattreatment, cobalt silicide (CoSi2) is 122 a and 122 b are formed (FIG.26). Then, useless Co is removed. Hereby cobalt silicide may be formedin the gate electrode, and the silicide using other metals (Ti, Ni,etc.) may be formed. Further, no silicide may be formed, and in thiscase, manufacturing of the gate and the formation of the transistor maybe performed, after tungsten silicide and SiN are formed as a film on apoly-silicon at the time of laminating the poly-silicon 110 of the gateelectrodes.

Next, a BPSG film 124 is formed on the whole substrate (FIG. 27).

Subsequently, the poly-silicon film 126 and a silicon nitride film 128,in which conductive type impurities of the P (phosphorus) on the wholesurface of the substrate are formed (FIG. 28). Afterwards, holes(hereinafter it may be called “transistor plug holes”) 130 a are formedby the photoresist process. The poly-silicon film 126 becomes a SelectedGate Line SGS of the memory transistor area.

Next by heating the substrate, thermal oxidation film 132 a and 132 bare formed (FIG. 29). The thermal oxidation films 132 a and 132 bbecomes the gate insulating films of the selection gate transistor SSTr.Subsequently, a silicon nitride film is formed on the whole surface ofthe substrate, and by performing anisotropic etching, a block siliconnitride 134 is formed (FIG. 29).

Next, a part of the thermal oxidation film 132 b is removed, by wetetching using hydrofluoric acid or dry etching using gas of fluoridesystem, thus thermal oxidation film 132 c is formed (FIG. 30).

Subsequently, after a block silicon nitride film 134 is removed andamorphous silicon (a-Si) films 136 are formed on the whole surface ofthe substrate, amorphous silicon films are formed by performing the CMPto the amorphous silicon films 136 (FIG. 31). In addition, instead ofthe amorphous silicon films 136, silicon film 136 a and 136 b may beformed by performing epitaxial growth to the single crystal silicon.

Next, photo resist 138 is formed and photo etching process is performed(FIG. 32).

Next, by forming titanium (Ti) film and performing heat treatmenttitanium silicide (TiSi) 140 a and 140 b are formed (FIG. 33). Inaddition, instead of titanium silicide (TiSi) 140 a and 140 b cobaltsilicide (CoSi2) may be formed, also, the silicide 140 a and 140 beither may or not may be formed.

Next, the silicon oxide film 142 is formed as the primetal insulationfilm (PMD). Then a contact hole is formed by photo etching process,then, after forming a slot for wiring in the silicon oxide film 142, atungsten (W) film is embedded, tungsten (W) plugs 144 a, 144 b and 144 cand a wiring 146 a and 146 b are formed. Next, silicon oxide film 148 isformed using TEOS (Tetraethoxysilane) (FIG. 33). Hereinafter, thesilicon nitride film that is formed using TEOS may be called “a TEOSfilm.”

Next, by forming poly-silicon films (or amorphous silicon films) andsilicon oxide films in turn, in which conductive impurities such as P(phosphorous) etc. are added in, poly-silicon films 150, 154, 158, 162and 166, and silicon oxide films 152, 156, 160, 164, are formed (FIG.34). Further, a silicon nitride film 168 is formed (FIG. 34).

Subsequently in the memory transistor area, memory plug holes 170 areformed to form a pillar shaped semiconductor (a body part) of the memorytransistor (FIG. 35). In addition, in this embodiment, the memory plugholes 170 are called “a memory plug holes 170”.

In addition, unevenness may be occurred on the surface of the memoryplug holes 170 as shown in FIG. 81 and FIG. 82, by various factors suchas: switching of the etching gas, at the time of forming this memoryplug holes 170; removal of the piles; materials of films 150 to 168 andso on. In FIG. 81, an example, in which poly-silicon films 150, 154,158, 162 and 166 on the surface of the memory hole 170 are excessivelyetched and unevenness is occurred on the surface of the memory plugholes 170, are shown. Even though the case like this, which theunevenness is occurred on the surface of the memory plug holes 170, thecross-sectional shape of the memory transistor area of the nonvolatilesemiconductor memory device 1 according to this embodiment is almostsymmetric to a central axis of the memory plug holes 170.

In FIG. 82, an example, in which silicon nitride films 150, 152, 156,160 and 164 on the surface of the memory plug holes 170 are excessivelyetched, and unevenness is occurred on the surface of the memory plughole 170 are shown. In addition, even though the case like this, whichthe unevenness is occurred on the surface of the memory plug holes 170,the cross-section of the memory transistor area of the nonvolatilesemiconductor memory device 1 according to this embodiment is almostsymmetric to a central axis of the memory plug holes 170.

Also, silicon nitride films 340 a, 340 b, 340 c and 340 d on the surfaceof the memory plug holes 170 may be formed so that dielectric constantof the film among each of the poly-silicon films 150, 154, 158, 162 and166 that become the word lines WL of the nonvolatile semiconductormemory device 1 according to this embodiment may be enhanced (FIG. 83).By doing so, change effect of the potential of the word lines WL may beefficiently transmitted to the pillar shaped semiconductor layer thatare formed in the memory plug holes 170 later.

Also in this embodiment, the silicon oxide films 152, 156, 160 and 164are formed (FIG. 34), alternatively, lamination films 152, 156, 160 and164 of the silicon oxide films/silicon nitride films/silicon nitridefilm may be formed (FIG. 84). By doing so, change effect of thepotential of the word lines WL may be efficiently transmitted to thepillar shaped semiconductor layer that are formed in the memory plugholes 170 later.

In addition, by various factors such as: switching of the etching gas atthe time of forming this memory plug holes 170, removal of the piles,materials of films 150 to 168 and so on, a shape of the memory plugholes 170 may become a forward taper shape (FIG. 85) or in a barrelshape (FIG. 86)

Next, a silicon oxide film, a silicon nitride film and silicon oxidefilm are sequentially laminating and thus what is called a ONO film 172are formed (FIG. 36). The silicon nitride film in the ONO films 172becomes a charge storage layer of the memory transistor.

Subsequently, by forming photoresist and performing etch back, a part ofthe ONO film 172 of the peripheral circuit area and the memorytransistor area are removed. In the memory plug holes 170 of the memorytransistor area, an ONO film 172 a and a photo resist 174 are remainedexcept for a layer (poly-silicon 166), in which the selection gatetransistor SDTr is formed, and a part of the silicon oxide film 164 atthe lower part of the poly-silicon layer 166 (FIG. 37).

Next, by removing photo resist 174 and performing heat treatment, athermal oxidation film 176 is formed in the layer (FIG. 38), in whichthe selected gate transistor SDTr is formed (poly-silicon 166). Inaddition, instead of forming this thermal oxidation film, a siliconoxide film 176 may be formed by the CVD method.

Subsequently, by forming a silicon nitride film on the whole substrateand performing anisotropic etching, spacer silicon nitride films 178 areformed (FIG. 39).

After removing the spacer silicon nitride films 178, by laminatingamorphous silicon films and performing CMP treatment, a pillar shapedamorphous silicon layers 180 are formed (FIG. 40). In addition, insteadof laminating the amorphous silicon films, poly-silicon is made to begrown with an epitaxial growth, by which poly-silicon layers 180 may beformed. Also, in the case that the poly-silicon are formed by selectiveepitaxial growth in the silicon inside of the lower layer selection gatetransistor SSTr, monosilicon 180 may be formed by the selectiveepitaxial growth method.

A taper etching is performed to silicon nitride 168; poly-silicon films150, 154, 158, 162 and 166, and the silicon oxide films 152, 156, 160and 164 so that the edge parts of each layer become stepwise shapes.Thus, silicon nitride film 168 a, poly-silicon film 150, 154 a, 158 a,162 a and 166 a, and silicon oxide films 152 a, 156 a 160 a and 164 aare formed (FIG. 41).

Next, interlayer insulation film (BPSG) 182 is formed, performing CMPtreatment, and planarized (FIG. 42).

Here, the memory transistor area may be divided as shown in FIG. 80 (B),FIG. 90 or FIG. 11. At the time, after forming the interlayer insulationfilm (BPSG) 182 and planarizing the BPSG with CMP, division patterns ofthe memory transistor are formed with a photolithography method and thusconductive films 150, 154, 158, 162 and 166, and the interlayerinsulation films 152, 156, 160, 164 and 168, are, etched. Then, bylaminating the interlayer insulation films (BPSG) again and planarizingit, array divisions like FIG. 80 (B) or FIG. 90 are formed. Further, incase of performing the array di-vision, the silicon substrate 100 of thememory area may be divided in advance into the area at the same degreeof the array divided by the STI102; or the silicon substrate 100 may aswell be divided.

Next, by photo etching process, the layer of the selection gatetransistor SDTr is divided, and the interlayer insulation films arelaminated into the area 186 a and 186 b (FIG. 43)

Subsequently, the interlayer insulation films (BPSG) 182 are removed,titan films are formed, and the heat treatment is performed, and thustitan silicide films are formed. In addition, instead of titan silicidefilms, cobalt silicide or nickel silicide etc. may be used, or thesilicides may as well be not formed. And silicon oxide films 187 as theprimetal insulation films (PMD) are formed; the CMP is performed; andthen planarized (FIG. 44). Afterwards by photo etching process, contactholes are formed; tungsten films are formed; and the CMP treatment isperformed. Thus, tungsten plugs 188 a, 188 b, 188 c, 188 d and 188 e areformed (FIG. 44).

Next, an aluminum (Al) films is formed and, via photo etching process,electrodes 190 a, 190 c, 190 d, 190 e and 190 f are formed (FIG. 44).

Subsequently, interlayer insulation films (BPSG) are formed; the CMPtreatment is performed; and then planarized (FIG. 44). Afterwards byphoto etching process, contact holes are formed, tungsten films areformed, and the CMP treatment is performed; thus tungsten plugs 196 aand 196 b are formed (FIG. 44). And the aluminum film (Al) is formedand, via photo etching process, electrodes 196 a and 190 b are formed(FIG. 44).

By the above-described process, the nonvolatile semiconductor memorydevice 1 of the present invention according to this embodiment may bemanufactured.

According to the nonvolatile semiconductor memory device according toone embodiment of the present invention and the manufacturing methodthereof, by forming the word lines with a common conductor layer pereach layer, the number of the word lines drive may be reduced, and thusreduction of the chip area may be realized.

Also in the nonvolatile semiconductor memory device according to oneembodiment of the present invention and the manufacturing methodthereof, a plurality of vertical type transistors that are connected inseries may be formed by 1 PEP, by laminating the lamination filmscorresponding to the number of the lamination layers of the memorytransistors in advance and formation hole patterns in a lump.

Also in the nonvolatile semiconductor memory device according to oneembodiment of the present invention and the manufacturing methodthereof, it is necessary to connect the selection gates to the upper andlower parts a plurality of vertical type transistors that are connectedin series to operate. Formation of the series structure with theplurality of the vertical type transistors that are connected in seriesto the selection gates can be performed simultaneously with PEP of 1 or2 a (memory transistor formation holes PEP).

Also in the nonvolatile semiconductor memory device according to oneembodiment of the present invention and the manufacturing methodthereof, the selection gate SGS of a plurality of vertical typetransistors that are connected in series and the word lines WL of eachmemory transistor can be set always to be a common potential per eachlayer. Therefore in either of the selection gate lines SGS and the wordlines WL, a layer structure may be adopted. Thereby the word lines canbe formed by rough PEP, by which the manufacturing process issimplified, thus cost reduction may be realized.

Second Embodiment

In this embodiment, the manufacturing process of another example of thenonvolatile semiconductor memory device of the present invention will beexplained using FIG. 45 to FIG. 77. Further in FIG. 45 to FIG. 77, aswell as with the first embodiment, a peripheral circuit area, in whichperipheral circuits such as a word line driver circuit and a senseamplifier circuit are formed, is shown at the left side; a memorytransistor area is shown at the right side. In the memory transistorarea, area Apart, area B part, and parts equivalent to the cross sectionof X-X′ and Y-Y′ are shown.

First, FIG. 45 is shown. By the same method with the first embodiment,STI202 a, 202 b, 202 c, 202 d, 202 e are formed on the semiconductorsubstrate 200 are formed (FIG. 45).

Next, sacrificial oxidation is performed on the substrate surface (notshown in the figures), and after the photo resist patterns are formed atthe desired position, boron (B) ions are implanted, and thus P-Well area204 is formed (FIG. 46). Also, after forming the photo resist patternare formed at the desired position, boron (B) ions are implanted nearthe surface of the substrate 200 and thus-channel implant area 206 a and206 b are formed, which adjusts threshold Vth of the transistor Here inaddition, like the first embodiment 1, the transistor that is formed atthe peripheral circuit area shows an example of the N-channel typetransistor, in which N-Well area are formed by implanting ions that addN-type in the desired area, and thus P-channel type transistor is formed(not shown in the figures).

Next, photo etching process, by which only the memory transistor area isopened, is performed; phosphorus (P) ions are implanted at the desiredposition of the memory transistor area; and thus a thick n+ area 208 isformed (FIG. 46). The n+ diffusion area 208 becomes the source line SL.

Next, silicon nitride film 209 (barrier silicon nitride film) is formedon the whole surface of the substrate, then subsequently, TEOS film orBPSG film 210 are formed on the whole surface of the substrate (FIG.46).

Next, poly-silicon (p-Si) film 212 is formed, in which conductive typeimpurities such as phosphorus (P) are added on the whole surface of thesubstrate, and subsequently, silicon nitride film 214 is formed on thewhole surface of the substrate (FIG. 46).

Next, photo resist is formed at the desired pattern, the poly-siliconfilm 212 and the silicon nitride film 214 are etched with aphotolithography process, and thus a poly-silicon film 212 a and asilicon nitride film 214 a are formed (FIG. 47).

Next, photo resist mask (not shown in the figures) is formed at theplace except for the peripheral circuit area; using the photo resistmask, a silicon oxide film 210 and a silicon nitride film (barriersilicon nitride film) 209 are etched, silicon nitride film 210 a at thememory transistor area is made remained; and the silicon oxide film 210and the silicon nitride film (barrier silicon nitride film) of theperipheral circuit area are removed (FIG. 48). Then subsequently, photoresist mask (not shown in the figures) is removed.

Subsequently, by removing a sacrificial oxidation film (not shown in thefigures) and performing heat treatment, the first thermally-oxidizedfilm (not shown in the figures) is formed.

Next, by forming a photo resist mask 216 a and 216 b in the desiredpattern and performing wet etching, a part of first thermally-oxidizedfilms, STI202 a and 202 b are removed by etching (FIG. 49). A thin filmtransistor for high speed operation is formed in the area removed byetching; and a thick film gate transistor for high voltage resist willbe formed at the part, where no removal by the etching are performed.

Afterwards by removing the photo resist mask 216 a and 216 b andperforming heat treatment, a second thermally-oxidized film (not shownin the figures) is formed.

Subsequently, a poly-silicon film 218, in which conductive impuritiessuch as P (phosphorus) are added, are formed (FIG. 50). Then apoly-silicon film 218 is etched with a predetermined pattern and thusgate electrodes 218 a and 218 b of the peripheral circuit area areformed (FIG. 51). At this time, in the memory transistor area,poly-silicon films 218 c, 218 d, 218 e and 218 f may as well remain uponetching condition.

Then photo resist is formed in the P-channel type transistor of theperipheral circuit area and the memory transistor area (not shown in thefigures); As ions or P ions are implanted into the N-channel typetransistor area of the peripheral circuit area; the N-type areas 220 a,220 b, 220 c and 220 d that are automatically shallow with the gateelectrodes 218 a and 218 b are formed (FIG. 51); then photo resist isremoved.

Next, a photo resist is formed in the N-channel type transistor area ofthe peripheral circuit area and the memory transistor area (not shown inthe figures); in the P-channel type transistor area of the peripheralcircuit area, for example B ions are implanted; P-type areas (not shownin the figures) that is automatically shallow with the gate electrodes(not shown in the figures) are formed; then, photo resist is removed.

Next, by forming a silicon nitride film on the whole surface of thesubstrate and performing anisotropic etching the silicon nitride filmsare made remained on at the both edges of the gate electrodes 218 a and218 b; then side walls 222 a, 222 b, 222 c and 222 d are formed (FIG.52). In addition, in the memory transistor area, upon the etchingcondition, side walls 222 e, 222 f, 222 g and 222 h may as well beformed at the side part of the poly-silicon films 218 c, 218 d, 218 dand 218 f, respectively.

Next, photo resist is formed in the P-channel type transistor area ofthe peripheral circuit area and the memory transistor area (not shown inthe figures); arsenic (As) ions are implanted into the N-channel typetransistor area of the peripheral circuit area; source/drain area 224 a,224 b, 224 c and 224 d are formed automatically with the side walls 224a, 224 b, 224 c and 224 d (FIG. 53); then afterwards the photo resist isremoved.

Next, photo resist is formed in the N-channel type transistor of theperipheral circuit area and the memory transistor area (not shown in thefigures); B ions are implanted into the P-channel type transistor areaof the peripheral circuit area; the source/drain area (not shown in thefigures) is shown automatically with the side walls (not shown in thefigures), then photo resist is removed.

Next, a silicon nitride film (the barrier silicon nitride film) 226 areformed on the whole surface of the substrate (FIG. 53).

Subsequently by forming a BPSG film 228 on the whole surface of thesubstrate and performing a CMP treatment, the BPSG film 228 isplanarized (FIG. 54).

Next, a silicon oxide film 230 is formed as a primetal layer; thensubsequently, contact holes 232 a, 232 b and 232 c are formed in thesilicon oxide film by the photo etching process (FIG. 55). Then, byforming a trench for wiring in the silicon oxide film 230 by the photoetching process and planarization the tungsten by such as the embeddedCMP, tungsten plugs 234 a, 234 b and 234 c, and wirings 235 a, 235 b and235 c are formed (FIG. 56). Then a TEOS film 236 is formed (FIG. 56).

Subsequently, by forming the poly-silicon films and the TEOS films, inwhich conductive impurities such as P are added, poly-silicon films 238,242, 246 and 250, and silicon oxide films 240, 244, 248 and 252, areformed (FIG. 57).

Next, taper etching process is performed so that edge parts of the eachlayer of the memory transistor area are set to be in the shape ofstairs. At first, photo resist mask 254 is formed in the predeterminedposition of the memory transistor area (FIG. 58).

Next, using the photo resist mask 254, the silicon oxide is 252 isetched and thus a silicon oxide film 252 a is formed (FIG. 59).

Then using the photo resist mask 254, poly-silicon film 250 a is etchedand thus a poly-silicon film 250 a is formed (FIG. 60).

Subsequently, the photo resist mask 254 is thinning, then the photoresist mask 254 a is formed (FIG. 61). And using photo resist mask 254a, the silicon oxide films 252 a and 248 are etched so that a siliconoxide films 252 b and 248 a are formed (FIG. 61).

Then, using the photo resist mask 254 a, a poly-silicon film 250 a and246 are etched so that a poly-silicon film 250 b and 246 a are formed(FIG. 62).

Subsequently, the photo resist mask 254 b is thinning so that a photoresist mask 254 c is formed (FIG. 63). And using the photo resist mask254 c, the silicon oxide films of 252 b 248 a and 244 are etched andthus silicon oxide films 252 c, 248 b and 244 a are formed (FIG. 63).

Next, using photo resist mask 254 c, poly-silicon films 250 b, 246 a and242 are etched so that poly-silicon films 250 c, 246 b and 242 a areformed (FIG. 64).

Then the photo resist mask 254 c is thinning so that a photo resist mask254 d is formed (FIG. 64). And, using the photo resist mask 254 d,silicon nitride films 252 c, 248 b, 244 a and 240 are etched so thatsilicon nitride films 252 d, 248 c, 244 b and 240 a are formed (FIG.65).

Next, using the photo resist mask 254 d, poly-silicon film 250 c, 246 b,242 a and 238 are etched so that poly-silicon films 250 d, 246 c, 242 band 238 a are formed (FIG. 66). By doing so, edge parts of the eachlayer are formed in the shape of stairs.

Also in the above-described embodiment 1, using the taper etchingexplained in this second embodiment, a silicon nitride film 168 a,poly-silicon films 150, 154 a, 158 a, 162 a and 166 a, and silicon oxidefilms 152 a, 156 a, 160 a and 164 a may be formed as shown in FIG. 41.

Next, the photo resist film 254 d is removed, then a silicon nitridefilm (barrier silicon nitride film) 255 is formed on the whole surfaceof the substrate (FIG. 67)

Subsequently, by forming the BPSG film 256 on the whole surface of thesubstrate and performing heat treatment (reflow treatment), surface ofthe BPSG film 256 is planarized (FIG. 67). Further by performing the CMPtreatment to the BPSG film 256, flatness of the surface of the BPSG film256 is made enhanced. Here, the memory transistor area may be divided asshown in FIG. 80 (B), FIG. 90 or FIG. 11. At the time, after forming theinterlayer insulation film (BPSG) 256 and planarizing the BPSG with CMP,division patterns of the memory transistor area are formed with thephotolithography method, and thus conductive films 238 a, 242 b, 246 cand 250 d, and the interlayer insulation films 240 a, 244 b, 248 c and254 d are etched. Then, by laminating the interlayer insulation filmsBPSG) 256 again and planarizing it, array divisions like FIG. 80 (B),FIG. 90 or FIG. 11 are formed. Further, in case of performing the arraydivision, the silicon substrate 100 of the memory transistor area may bedivided in advance into the area at the same degree of the array dividedby the STI102; or the silicon substrate 200 may as well be not divided.Afterward, a poly-silicon film 258, in which conductive impurities suchas P (phosphorus) are added, and a silicon nitride 260 are formed (FIG.67)

Next in the memory transistor area, holes 262 to form a pillar shapedsemiconductor (a body part) of the memory transistor are formed (FIG.68). Further in this embodiment, the holes 262 are called “memory plugholes 262”.

In addition, unevenness may be occurred on the surface of the memoryplug holes 262 as well as with those shown in FIG. 81 and FIG. 82 of theabove-described first embodiment by various factors such as switching ofthe etching gas at the time of forming the memory plug holes 262,removal of the piles, materials of films 238 to 252 and so on. Inaddition, even though the case like this, which the unevenness isoccurred on the surface of the memory plug holes 262, thecross-sectional shape of the memory transistor area of the nonvolatilesemiconductor memory device 1 according to this embodiment is almostsymmetric to a central axis of the memory plug holes 262.

Also as well as with those shown in FIG. 83 of the above-described firstembodiment 1, silicon nitride films are formed on the surface of thememory plug holes 262; thus, dielectric constant of the films, which areamong each of the poly-silicon films 238, 242, 246 and 250 that becomethe word lines of the nonvolatile semiconductor memory device 1according to this embodiment, may be made enhanced. By doing so, effectof the potential change of the word lines WL may be transmittedeffectively to the pillar-shaped semiconductor layers formed later inthe memory plug holes 262.

And as well as with those shown in FIG. 84 of the above-described firstembodiment, the lamination films with silicon oxide films/siliconnitride films/silicon oxide films may be formed respectively in thisembodiment. By doing so, effect of the potential change of the wordlines WL may be transmitted effectively to the pillar-shapedsemiconductor layers formed later in the memory plug holes 262.

In addition, the shapes of the memory plug holes 262 may become aforward taper shape or a barrel shape as well as with those shown inFIG. 85 and FIG. 86 of the above-described first embodiment, by variousfactors such as switching of the etching gas at the time of forming thememory plug holes 262, removal of the piles, materials of films 238 to252 and so on.

After forming the memory plug holes 262, phosphorus (P) ions may beimplanted into the whole surface of the substrate, and may be implantedagain into the n+ diffusion area 208, which becomes the source line SL(not shown in the figures).

Next, a TEOS film 264 is formed on the whole surface of the substrate(FIG. 69). The TEOS film 264 is formed to the bottom parts of the memoryplug holes 262, as shown in FIG. 69. Here, instead of forming the TEOSfilm 264, an oxidation film may be formed by thermal oxidation method;in this case, as well as with the first embodiment, oxidation films maybe formed only on the poly-silicon part of the side wall of the memoryplug holes 262 and the silicon substrate of the bottom part of thememory plug holes 262.

Subsequently, anisotropic etching is performed to the TEOS film 264 sothat the TEOS film 264 a is formed (FIG. 70). Then in the TEOS film 264,the bottom parts of the memory plug holes 262 are set to be etched.

Then an amorphous silicon film 266 are formed (FIG. 70).

Next, the amorphous silicon film 266 are etch backed and made it recededuntil it become an amorphous silicon films 268 a (FIG. 71). Next, theTEOS film 264 a inside the memory plug holes 262 is removed, and then asilicon oxide film, a silicon nitride film and a silicon oxide film arelaminated in turn so that what is called an ONO film 270 are formed(FIG. 71). The ONO film becomes a charge storage layer of the memorytransistor. Further, the silicon oxide film of the ONO film 270 mayinclude the TEOS film.

Subsequently, by performing the anisotropic etching to the ONO film 270,a bottom part of the ONO film 270 is removed so that the ONO film 270 aare formed (FIG. 72). Next, an amorphous silicon film 272 is formed,etch backed and made it receded until it become an amorphous siliconfilms 272 a (FIG. 72). Next, an area, where the ONO films 270 a of theside wall inside of the memory plug holes 262 are removed to a degreethat a part of the silicon oxide 252 is exposed (FIG. 72). Then, a TEOSfilm 274 is formed on the whole surface of the substrate (FIG. 72).Also, thermal oxidation films may be formed instead of the TEOS. In thiscase, oxidation films are formed only on the poly-silicon of the sidewall of the memory plug holes 262 and the poly-silicon parts of thebottom parts of the memory plug holes 262.

Next, by performing the anisotropic etching to the TEOS film 274, thebottom part of the TEOS film 274 is removed so that TEOS films 274 a areformed (FIG. 73).

Next, by forming an amorphous silicon film 276 and performing the CMPtreatment, an amorphous silicon film 276 is planarized (FIG. 74).

Subsequently by photo etching process, the layer of the selection gatetransistor SDTr are divided (FIG. 75), BPSG film 280 is accumulated inthe area 278 a and 186 b; and then the CMP treatment is performed (FIG.76).

Next, by the photo etching process, contact holes 282 a, 282 b, 282 c,282 d, 282 e, 282 f and 282 g are formed (FIG. 76).

After forming the lamination films of titanium and titanium nitride (notshowing in the figures), by forming a tungsten film and performing CMPtreatment, tungsten plugs 284 a, 284 b, 284 c, 284 d, 284 e, 284 f and284 g are formed into contact holes 282 a, 282 b, 282 c, 282 d, 282 e,282 f and 282 g a (FIG. 77).

Next, aluminum/copper (Al, CU) films are formed; photo resist mask (notshown in the figures) is formed; and patterning is performed by photoetching process so that wirings 286 a, 286 b, 286 c, 286 d, 286 e, 286f, 286 g and 286 h are formed (FIG. 78). Then photo resist mask isremoved (FIG. 77).

By the above-described process, the nonvolatile semiconductor memorydevice 1 according to this embodiment may be manufactured.

According to the nonvolatile semiconductor memory device and themanufacturing method thereof according to one embodiment of the presentinvention, number of word line drivers may be reduced by forming theword line per each layer with a common conductor layer, and thusreduction of chip area may be realized.

And in the nonvolatile semiconductor memory device according to oneembodiment of the present invention and the manufacturing methodthereof, a plurality of vertical type transistors that are connected inseries may be formed by 1 PEP, by laminating the lamination filmscorresponding to the number of the lamination layers of the memorytransistors in advance and formation hole patterns in a lump.

Also in the nonvolatile semiconductor memory device according to oneembodiment of the present invention and the manufacturing methodthereof, it is necessary to connect the selection gates to the upper andlower parts of vertical type transistors that are connected in series tooperate a plurality of the transistors. Also the formation of the seriesstructure with the plurality of the vertical type transistors that areconnected to the selection gates in series may be performedsimultaneously with the PEPs of 1 or 2 (memory transistor formation PEP)

Further in the nonvolatile semiconductor memory device according to oneembodiment of the present invention and the manufacturing methodthereof, the source side selection gates SGS of the plurality ofvertical type transistors that are connected in series and the wordlines WL of each of the memory transistors, as a matter of operation,can be set to be a common potential per each layer all the time.Therefore, the layer structure may be applied to both of the selectiongate lines SGS and the word lines WL. As thus described, the word linescan be formed by the rough PEP, by which the manufacturing process maybe simplified and thus the cost reduction may be realized.

Third Embodiment

In this embodiment, a film including a nanocrystal film in the chargestorage layer of the nonvolatile semiconductor memory device of thepresent invention. For example, the charge storage layer is set to be alamination structure configured to a silicon oxide film, a nanocrystalfilm and a silicon oxide film. As the nanocrystal films, a silicon oxidefilm including the nanocrystal of the silicon may be used. In thenonvolatile semiconductor memory device according to this embodiment,charges are held in the nanocrystal of the silicon that aredisintegrated and distributed in this nanocrystal film.

Further in this embodiment, the nanocrystal film including thenanocrystal of the silicon is used; however, nanocrystal of metals orthe other nanocrystal of conductors, such as cobalt (Co), tungsten (W),silver (Ag), gold (Au), platinum (Pt), etc. In addition, the nanocrystalis also called “metal nano dot” and “nanocrystal”.

Also in this embodiment, silicon oxide film, nanocrystal film andsilicon oxide film are applied for the charge storage layers; a singlelayer structure of the insulation film such as silicon oxide film, inwhich the three layers are formed serially and in which nanocrystal ofsilicon, metals and the other conductors are contained, may be applied.

Fourth Embodiment

In this embodiment, another example of the configuration of the memorytransistor area in the nonvolatile semiconductor memory device of thepresent invention will be explained. In addition, the otherconfiguration will not be explained again, for they are same with theabove-described first embodiment, the second embodiment and the thirdembodiment.

In the nonvolatile semiconductor memory device according to oneembodiment of the present invention, conductor layers and the interlayerfilms are etched in a taper shape so that steps are formed. Hereby anexample, in which two adjacent memory transistor areas are formed, isshown in FIG. 79. FIG. 79 is a diagram, in which the conductor layers ofthe memory transistor area of the nonvolatile semiconductor memorydevice of the present invention according to this embodiment are seenfrom the top part. The conductor layers 300 to 306 show one memorytransistor area, in which 300 shows a first conductor layer; 302 shows asecond conductor layer; 304 shows a third conductor layer; and 306 showsa fourth conductor layer. And the conductor layers 308 to 314 show theadjacent memory transistor areas, in which 308 shows a first conductorlayer; 310 shows a second conductor layer; 312 shows a third conductorlayer; and 314 shows a fourth conductor layer. In addition, “A” is alength of Y′ to Y direction of the two adjacent memory transistors, and“B” is a length of the X to X′ direction.

Thus, in the case that the adjacent memory transistor areas are formed,each of the memory transistor areas may be formed separately.

Also in FIG. 80, another example of two memory transistor areas of thenonvolatile semiconductor memory device according to this embodiment isshown. FIG. 80 (A) is a diagram, in which the conductor layers of thememory transistor area of the nonvolatile semiconductor memory device ofthe present invention according, to this embodiment are seen from thetop part. 320 show a first conductor layer; 322 show a second conductorlayer; 324 show a third conductor layer; and 326 and 328 show fourthconductor layers.

In the memory transistor area shown in FIG. 80 (A) (B), by removing withetching the conductor layers 320, 324 and 326 along with X to X′ to inthe vicinity of the centre, two memory transistor areas of: a memorytransistor area configured to conductor areas 320 a, 322 a, 324 a and326 and; the memory transistor area configured to conductor layers 320b, 322 b, 324 b and 328, may be formed. In the memory transistor areashown in FIG. 80, the length of the Y to Y′ direction may be shortenedas compared with the memory transistor area shown in FIG. 79, and thusthe area of the memory transistor area may be reduced.

Subsequently an example, in which the 10 adjacent memory transistorareas are formed, is shown in FIG. 89. FIG. 89 is a diagram, in whichthe conductor layers of the memory transistor area of the nonvolatilesemiconductor memory device of the present invention according to thisembodiment are seen from the top part. In addition, “A” is equivalent tothe length of the Y to Y′ direction of the two adjacent memorytransistors shown in FIG. 79; and “B” is equivalent to the length of theX to X′ direction.

In the nonvolatile semiconductor memory device according to thisembodiment shown in FIG. 89, 330 shows a first conductor layer; 332shows a second conductor layer; 334 shows a third conductor layer; and336 a to 336 j show fourth conductor layer.

In the memory transistor area shown in FIG. 89, as shown in FIG. 90, theconductor layers 330, 332 and 334 are removed by etching along with theX′ to X direction between the fourth conductor layers 336 a to 336 j, bywhich conductor layers 330 a to 330 j, conductor layers 332 a to 332 j,conductor layers 334 a to 334 j, and conductor layers 336 a to 336 j areformed.

In the memory transistor area shown in FIG. 89, a overhead view diagram,in which the conductor layers 330, 32 and 334 are removed by the etchingalong with the X′ to X direction between the fourth conductor layers 336a to 336 j and thus ten memory transistor areas are formed, are shown inFIG. 90. The memory transistor area configured to conductor layers 330a, 332 a, 334 a and 336 a the memory transistor areas configured to theconductor layers 330 b, 332 b, 334 b and 336 b, the memory transistorareas configured to the conductor layers 330 c, 332 c, 334 c and 336 c,the memory transistor areas configured to the conductor layers 330 d,332 d, 334 d and 336 d; the memory transistor areas configured to theconductor layers 330 e, 332 e, 334 e and 336 e; the memory transistorareas configured to the conductor layers 330 f, 332 f, 334 f and 336 f;the memory transistor areas configured to the conductor layers 330 g,332 g, 334 g and 336 g; the memory transistor areas configured to theconductor layers 330 h, 332 h, 334 h and 336 h; the memory transistorareas configured to the conductor layers 330 i, 332 i, 334 i and 336 i;and the memory transistor areas configured to the conductor layers 330j, 332 j, 334 j and 336 j are formed, thus totally ten memory transistorareas are formed. The memory transistor areas shown in FIG. 90 may beshorten the length of the Y to Y′ direction as compared with the memorytransistor areas shown in FIG. 79, therefore the areas of the memorytransistor areas may be reduced.

Further in this embodiment, an example the nonvolatile semiconductormemory device of the present invention, in the case that it is formed bylaminating the four conductor layers so that ten memory transistor areformed, are explained. However, the nonvolatile semiconductor memorydevice of the present invention is not limited to this; an arbitrarynumber of the conductor layers may be laminated and an arbitrary numberof the memory transistor areas may be formed simultaneously.

Also, an example, in which the adjacent seven memory transistor areasare formed into two columns, is shown in FIG. 91 and FIG. 92. FIG. 91 isa diagram, in which the conductor layers of the memory-transistor areasof the nonvolatile semiconductor memory device of the present inventionaccording to this embodiment are seen from the top part. In addition,“A” is equivalent to a length of Y′ to Y direction of the two adjacentmemory transistor areas shown in FIG. 79, and “B” is equivalent to alength of the X′ to X direction.

In the nonvolatile semiconductor memory device according to thisembodiment shown in FIG. 91, 340 shows a first conductor layer; 342shows a second conductor layer; 344 shows a third, conductor layer; and346 a to 346 n show fourth conductor layers.

In the memory transistor area shown in FIG. 91, as shown in FIG. 92, theconductor layers 340, 342 and 344 are removed by etching along with theX′ to X direction and the Y′ to Y direction between the fourth conductorlayers 346 a to 346 n, by which conductor layers 340 a to 340 n,conductor layers 342 a to 342 n, conductor layers 344 a to 344 n, andconductor layers 346 a to 346 n are formed.

In FIG. 92, the memory transistor area configured to conductor layers340 a, 342 a, 344 a and 346 a; the memory transistor areas configured tothe conductor layers 340 b, 342 b, 344 b and 346 b, the memorytransistor areas configured to the conductor layers 340 c, 342 c, 344 cand 346 c, the memory transistor areas configured to the conductorlayers 340 d, 342 d, 344 d and 346 d, the memory transistor areasconfigured to the conductor layers 340 e, 342 e, 344 e and 346 e, thememory transistor areas configured to the conductor layers 340 f, 342 f,344 f and 346 f; the memory transistor areas configured to the conductorlayers 340 g, 342 g, 344 g and 346 g, the memory transistor areasconfigured to the conductor layers 340 h, 342 h, 344 h and 346 h, thememory transistor areas configured to the conductor layers 340 i, 342 i,344 i and 346 i, and the memory transistor areas configured to theconductor layers 340 j, 342 j, 344 j and 346 j are formed, thus totallyfourteen memory transistor areas are formed. The memory transistor areasshown in FIG. 92 may be shorten the length of the Y to Y′ direction ascompared with the memory transistor areas shown in FIG. 79, thereforethe areas of the memory transistor areas may be reduced.

In addition here, an example the nonvolatile semiconductor memory deviceof the present invention, in the case that it is formed by laminatingthe four conductor layers so that fourteen memory transistor areas areformed, are explained. However, the nonvolatile semiconductor memorydevice of the present invention is not limited to this; an arbitrarynumber of the conductor layers may be laminated and an arbitrary numberof the memory transistor areas may be formed simultaneously.

Further in FIG. 11, an example, in which a plurality number of thememory transistor areas shown in FIG. 92 are formed, is shown. As shownin FIG. 11, in the nonvolatile semiconductor memory device according tothis embodiment, the plurality of the memory transistor areas may bedisposed efficiently.

In addition here, an example the nonvolatile semiconductor memory deviceof the present invention, in the case that it is formed by laminatingthe four conductor layers so that two fourteen-memory-transistor areasare formed, are explained. However, the nonvolatile semiconductor memorydevice of the present invention is not limited to this; an arbitrarynumber of the conductor layers may be laminated and an arbitrary numberof the memory transistor areas may be formed simultaneously.

In addition, in the above-described embodiment 1, a case is shown, wherea metal wiring 146 a of the bottom layer is formed after forming thetransistor and the source side selection gate (SGS) in the peripheralcircuit area and the memory cell areas are stacked afterward. The caseis not limited to this formation process; for example, a metal wiringmay be formed on the top layer after stacking the memory cell areas.

An example, where the metal wiring is formed on the top layer, is shownin FIG. 93. In the example, tungsten (W) plug 144 a, 144 b and thewiring 146 a, which are shown in the peripheral circuit area of theabove-described FIG. 33, are not formed. After the interlayer insulationfilm 182 is formed in the peripheral circuit area shown in theabove-described FIG. 42, and shifted to a process of forming the metalwiring shown in FIG. 93. In FIG. 93, a contact hole is formed by photoetching process, a tungsten film is formed and CMP process is performed.Thereby, the tungsten plugs 301 a, 301 b, 301 c, 301 d, 188 b, 188 c,188 d and 188 e are formed.

Next in FIG. 93, an aluminum (AL) film is formed, and the electrodes 302a, 302 b, 302 c, 302 d, 190 b, 190 c, 190 d, 190 e and 190 f are formedvia the photo etching process. In the next place, in FIG. 93, theinterlayer insulation film (BPSG) 192 is formed, the CMP process isperformed to perform planarization. Afterwards, a contact hole is formedby the photo etching process, a tungsten film is formed and the CMPprocess is performed. Thereby, the tungsten plugs 303 a, 303 b and 194 bare formed. Further, in FIG. 93, an aluminum (Al) film is formed, andthe electrodes 304 a, 304 b and 196 b are formed.

As above, in the peripheral circuit area, influence of the heat processperformed at the time of stacking the memory cell area may be reduced byforming the metal wiring from the top layer rather than by forming themetal wiring at the bottom layer.

In addition, in a case where the nonvolatile semiconductor memory deviceshown in the above-described FIG. 44, FIG. 77 and FIG. 93 is formed, thethermal history is different in the upper layer selection gatetransistor SDTr and the lower layer selection gate transistor SSTr,because the nonvolatile semiconductor memory device is formed from thebottom layer section. In particular, the bottom layer selection gatetransistor SSTr affect the thermal history larger than the upper layerselection gate transistor SDTr; therefore, measures to maintain theelectric connection of the off electric current characteristics with thememory array area well is required. As measures for this, an example, inwhich a gate length L1 of the upper layer selection gate transistor SDTrand the gate length L2 of the lower layer selection gate transistor SSTrbecomes the different lengths, are explained as follows.

In FIG. 93, the gate length L1 of the upper layer selection gatetransistor SDTr and the gate length L2 of the lower layer selection gatetransistor SSTr are shown. In this case, the gate length L2 of the lowerlayer selection gate transistor SSTr is set longer than the gate lengthL1 of the upper layer selection gate transistor SDTr. Hereinafter,setting examples of the gate length L1 and L2 will be respectivelyexplained referring to FIG. 93 to FIG. 95.

In FIG. 93, D1 shows a distance between the lower layer source line SLand the lower layer selection gate transistor SSTr; L2 shows a gatelength of the lower selection gate transistor SSTr; D2 shows a distanceof joint between the lower layer selection gate transistor SSTr and thememory array at the bottom layer; D3 shows a distance of joint betweenthe memory array at the top layer and the upper layer selection gatetransistor-SDTr; also in FIG. 93, D4 shows a distance between the upperlayer selection gate transistor SDTr and the body silicon top layer.

FIG. 94 is a diagram showing one example of each drain profile of thelower selection gate transistor SSTr before or after re-re-annealing,and a drain profile of the upper selection gate transistor SSTr afterthe re-annealing. In the diagram, depth of the diffusion layer became0.25 μm, when applying 950° C./40 sec which is equivalent to the heatprocess forming the upper layer selection gate transistor SDTr and thememory array. By the above, it becomes apparent that depth of thediffusion layer in the lower selection gate transistor SSTr differs inthe depth 0.05 μm, as compared to depth of the diffusion layer of theupper layer selection gate transistor SDTr. By this, it became furtherapparent that the gate length L2 of the lower selection gate transistorSSTr is required to be lengthened in at least equal to or more than 0.05μm as compared to the gate length L1 of the upper layer selection gatetransistor SDTr.

FIG. 95 is a diagram showing an example of difference of threshold (athreshold change amount delta Vth) considering the process difference inthe case of changing the gate length L of the selection gate transistor.In the diagram, an example is shown, in which three drain diffusionconditions 140 keV, 160 keV, 180 keV are set and the length of the gatelength L are changed. Together with the three conditions, it becameapparent that the unevenness of threshold change amount delta Vth islarge in the case that the gate length L is set to be less than 0.2 μm;it became further apparent that the difference of threshold changeamount delta Vth becomes small in the case that the gate length L is setto be equal to or more than 0.2 μm.

By the result shown in the above-described FIG. 94 and FIG. 95, itbecame apparent that the gate length L1 of the upper layer selectiongate transistor SDTr and the gate length L2 of the lower layer selectiongate transistor SSTr both require lengths of equal to or more than 0.2μm. It became further apparent that the gate length L2 of the lowerselection gate transistor SSTr is required to be lengthened at leastequal to or more than 0.05 μm as compared to the gate length L1 of theupper layer selection gate transistor SDTr.

It is preferred that the length of the above-described gate lengths beset to be different, and that the following measures (1) to (3) beperformed.

(1) To lengthen the distance D1 between the lower layer selection gatetransistor SSTr and the source line SL than the distance D3 of jointbetween the memory array of the top layer and the upper layer selectiongate transistor SDTr.

(2) To lengthen the distance D2 of joint between the lower selectiongate transistor SSTr and the memory array at the bottom layer, longerthan the distance D4 (Refer to FIG. 93.) between the upper layerselection gate transistor STDr and the body silicon top layer.

(3) To set the distance D1 between the lower gate transistor SSTr andthe source line SL to be equal to or more than 300 nm.

By performing the above-described measures (1) to (3), increase of theoff electric current caused by the extent of the diffusion layer bydifferent thermal histories may be improved, and the concentration ofthe diffusion layer of the gate connection section may be maintained inhigh concentration. Further, by setting the gate length L2 of the lowerlayer selection gate transistor SSTr and the gate length L1 of the upperlayer selection gate transistor SDTr to be different lengths, an overlapamount of gate electrodes of the upper layer selection gate transistorSDTr and the lower layer selection gate transistor SSTr and the draindiffusion layer is set to save sufficiently together with maintainingsatisfactory contact resistance, and thus the driving force may beimproved.

In addition, in the above-described embodiments, a case is shown, inwhich an ONO film is applied as a gate insulation film including thecharge storage layer; however, the present invention is not limited tothis. For example, an ONA film, a SANOS film and such may be applied.That is to say, anything is possible as far as the gate insulation filmmay be the film that includes the charge storage layer, which does notmean limitation of the materials.

What is claimed is:
 1. A nonvolatile semiconductor memory devicecomprising: a first structure having a first semiconductor layer, firstelectrode layers, first insulating layers and a first memory portion,the first semiconductor layer extending in a first direction, the firstelectrode layers and the first insulating layers alternately stacked inthe first direction, the first memory portion provided between the firstsemiconductor layer and one of the first electrode layers, and the firstelectrode layers including a first contact region formed in a shape ofstairs; and a second structure having a second semiconductor layer,second electrode layers, second insulating layers and a second memoryportion, the second semiconductor layer extending in the firstdirection, the second electrode layers and the second insulating layersalternately stacked in the first direction, the second memory portionprovided between the second semiconductor layer and one of the secondelectrode layers, and the second electrode layers including a secondcontact region formed in a shape of stairs, and wherein the firststructure and the second structure are arranged in a second directioncrossing the first direction, and the first contact region and thesecond contact region are not arranged between the first structure andthe second structure.
 2. The nonvolatile semiconductor memory deviceaccording to claim 1, wherein the first contact region is arranged on aside opposite to a region between the first structure and the secondstructure in the second direction, and the second contact region isarranged on the side opposite to the region between the first structureand the second structure in the second direction.
 3. The nonvolatilesemiconductor memory device according to claim 1, further comprising: afirst insulation film formed around the first semiconductor layer; acharge storage layer formed around the first insulation film; a secondinsulation film formed around the charge storage layer; and a pluralityof third insulation films formed around the second insulation film, thethird insulation films being formed between the first electrode layers,respectively.
 4. The nonvolatile semiconductor memory device accordingto claim 1, further comprising: a plurality of plugs, each of the plugsbeing connected electrically to an upper surface of each of the firstelectrode layers in the first contact region formed in the shape ofstairs.
 5. The nonvolatile semiconductor memory device according toclaim 4, wherein each of the first electrode layers is connected to aword line driver via each of the plugs.
 6. The nonvolatile semiconductormemory device according to claim 1, further comprising: a thirdstructure having a third semiconductor layer, third electrode layers,third insulating layers and a third memory portion, the thirdsemiconductor layer extending in the first direction, the thirdelectrode layers and the third insulating layers alternately stacked inthe first direction, the third memory portion provided between the thirdsemiconductor layer and one of the third electrode layers, and the thirdelectrode layers including a third contact region formed in a shape ofstairs; and a fourth structure having a fourth semiconductor layer, afourth electrode layers, a fourth insulating layers and a fourth memoryportion, the fourth semiconductor layer extending in the firstdirection, the fourth electrode layers and the fourth insulating layersalternately stacked in the first direction, the fourth memory portionprovided between the fourth semiconductor layer and one of the fourthelectrode layers, and the fourth electrode layers including a fourthcontact region formed in a shape of stairs, and wherein the thirdstructure and the fourth structure are arranged in the second direction,and the third contact region and the fourth contact region are notarranged between the third structure and the fourth structure.
 7. Thenonvolatile semiconductor memory device according to claim 6, whereinthe third contact region is arranged on a side opposite to a regionbetween the third structure and the fourth structure in the seconddirection, and the fourth contact region is arranged on the sideopposite to the region between the third structure and the fourthstructure in the second direction.
 8. The nonvolatile semiconductormemory device according to claim 6, wherein the third structure and thefirst structure are arranged in a third direction crossing the firstdirection and the second direction, the fourth structure and the secondstructure are arranged in the third direction, the first contact region,the second contact region, the third contact region and the fourthcontact region are not arranged between the third structure and thefourth structure, the first contact region, the second contact region,the third contact region and the fourth contact region are not arrangedbetween the first structure and the third structure, and the firstcontact region, the second contact region, the third contact region andthe fourth contact region are not arranged between the second structureand the fourth structure.
 9. The nonvolatile semiconductor memory deviceaccording to claim 6, wherein the third contact region is provided at anedge region of the third electrode layers in the third direction and ona side opposite to a region between the third structure and the fourthstructure, and the fourth contact region is provided at an edge regionof the fourth electrode layers in the third direction and on the sideopposite to the region between the third structure and the fourthstructure.
 10. The nonvolatile semiconductor memory device according toclaim 9, wherein the third structure is arranged in the third directionfor the first structure, and the fourth structure is arranged in thethird direction for the second structure.
 11. The nonvolatilesemiconductor memory device according to claim 6, wherein the secondstructure is arranged adjacent to the third structure in the seconddirection, and the second contact region is arranged to face the thirdcontact region in the second direction.
 12. The nonvolatilesemiconductor memory device according to claim 11, wherein the thirdcontact region is arranged on a side opposite to a region between thethird structure and the fourth structure in the second direction, andthe fourth contact region is arranged on the side opposite to the regionbetween the third structure and the fourth structure.
 13. Thenonvolatile semiconductor memory device according to claim 6, whereinthe third structure is arranged in the second direction, and the fourthstructure is arranged in the second direction, the third contact regionand the fourth contact region are not arranged between the thirdstructure and the fourth structure.
 14. The nonvolatile semiconductormemory device according to claim 1, further comprising a thirdsemiconductor layer, a third memory portion, a fourth semiconductorlayer and a fourth memory portion: the third memory portion is providedbetween the third semiconductor layer and the first electrode layershared with the first memory portion, the third memory portion isadjacent to the first memory portion in the second direction, and thefourth memory portion is provided between the fourth semiconductor layerand the first electrode layer shared with the first memory portion, thefourth memory portion is adjacent to the first memory portion in thethird direction.